Written by Chad Panton, Co-founder, ISI Energy · Last reviewed October 2026
Why "which is best?" is the wrong first question
Two neighbors can have the same panels, the same inverter, and the same roof, and be in completely different financial arrangements. One owns an asset. The other has a 20-year payment obligation attached to the house. Neither is a mistake by itself; what matters is that each of them chose it knowingly.
So instead of asking which option is best, ask: under this agreement, who owns what, who gets paid what, what changes over time, and what happens when I sell? Below is how each option answers those questions, followed by a checklist you can use on any proposal.
Option 1: Cash purchase
Ownership: You, from day one.
Payments: The full price up front. No monthly payment, no escalator.
Incentives: The Illinois Shines REC contract is held by the Approved Vendor, and the Disclosure Form states how much of that value reaches you, often as a price reduction. You decide whether to take the ComEd Distributed Generation Rebate, which is not reversible once taken. (Sources: illinoisshines.com/faqs; ComEd Net Metering FAQ.)
Maintenance: Yours, backed by manufacturer warranties and the installer's workmanship warranty. Read both.
At sale: The system transfers with the house like any fixture.
Tax treatment: Yours to discuss with a tax professional. Note that the IRS states the federal Residential Clean Energy Credit (section 25D) is not allowed for expenditures made after December 31, 2025, with an expenditure treated as made when installation is completed. (Source: irs.gov, FAQs on Public Law 119-21.)
Option 2: Solar loan
Ownership: You.
Payments: A monthly loan payment to a lender for a set term.
Incentives: Same as a cash purchase, because you own the system.
Maintenance: Yours, as above.
At sale: The loan typically must be paid off at closing or assumed by the buyer, depending on the lender.
What to scrutinize: The interest rate, the term, whether a dealer fee is built into the system price (ask for the cash price and the financed price side by side), whether the payment changes at any point in the term, and what happens if you prepay.
Option 3: Solar lease
Ownership: The leasing company. The system is on your roof but is not yours.
Payments: A fixed monthly amount for the equipment, regardless of how much it produces. Many leases include an annual escalator, a percentage increase every year.
Incentives: Typically retained by the owner, including REC value and the ComEd rebate. The Disclosure Form must state this. (Source: illinoisshines.com/faqs.)
Maintenance: Typically the owner's responsibility, including monitoring and repairs.
At sale: The lease must be transferred to a buyer who qualifies with the leasing company, or bought out according to the contract's schedule.
What to scrutinize: The escalator percentage, the production guarantee if any, the end-of-term options (renew, buy, remove), and the transfer and buyout terms.
Option 4: Power purchase agreement
Ownership: The PPA provider.
Payments: A price per kWh for the electricity the system produces. Because production varies, the payment is higher in summer and lower in winter. Escalators are common here too.
Incentives: Typically retained by the owner, as with a lease.
Maintenance: Typically the owner's.
At sale: Transfer or buyout, as with a lease.
What to scrutinize: The starting price per kWh, the escalator, the production assumptions used in the sales presentation, and what you pay the utility for electricity the system does not cover. Remember that for new ComEd systems, exported electricity earns supply-only credits, so understand how the PPA's per-kWh price interacts with your actual bill. See How solar billing works for ComEd customers.
In every option: you remain the utility's customer and continue to receive a utility bill.
The seven-question checklist for any proposal
Put each proposal next to its Disclosure Form and answer these in writing:
1. Who owns the system? Me, or a company.
2. Who receives the Illinois Shines REC value, and how? Price reduction, pass-through payment, or kept by the owner.
3. Who receives the ComEd Distributed Generation Rebate?
4. What is the payment in year one, and what is it in the final year? If there is an escalator, do the multiplication.
5. What are the production assumptions, and what happens if actual production is lower?
6. What happens when I sell the house? Transfer requirements, buyer qualification, buyout schedule.
7. Who fixes it when something breaks, and who pays?
If a salesperson cannot answer all seven from the documents in front of you, you do not have enough information to sign.
A note on escalators
An escalator of a few percent a year sounds small. Over a 20 or 25 year term it is not. Ask for the payment schedule for every year of the term, not the first-year payment and a percentage. Then ask yourself whether you are comfortable with the final-year number. We are not predicting what utility rates will do, and neither should anyone selling you a system; the escalator is a contractual fact, while utility rates are not.
What this means for you
There is no universally right answer, and anyone who tells you one option is always better is selling that option. The right answer is the one you understood before you signed. ISI Energy does not offer financing or own systems; we walk through all four options with your own bills on the screen and send you a written summary so you can evaluate whatever a licensed partner later presents. Book a free consultation or call (224) 395-1162. For the side-by-side table, see Solar Financing Options.
Frequently asked questions
What is the difference between a solar lease and a PPA?
Under a lease you pay a fixed monthly amount for equipment a company owns on your roof. Under a PPA you pay a per-kWh price for the electricity that company's system produces, so the payment varies with the season. In both cases you do not own the system.
Who gets the incentives under a solar lease or PPA?
Typically the system owner keeps the Illinois Shines REC value and any ComEd Distributed Generation Rebate. The Disclosure Form the Approved Vendor must give you before signing states exactly how incentives are handled on your project. Source: illinoisshines.com/faqs.
Can I sell my house with a solar lease or PPA?
Yes, but the agreement typically must be transferred to a buyer who qualifies with the provider, or bought out according to the contract. Ask for the transfer and buyout terms in writing before you sign.
Sources
- Illinois Shines, "Consumer FAQs," illinoisshines.com/faqs/
- Illinois Shines, "About the Program," illinoisshines.com/about/
- ComEd, "Net Metering Frequently Asked Questions" (2025)
- IRS, "FAQs for modification of sections 25C, 25D ... under Public Law 119-21," irs.gov
ISI ENERGY LLC is a sales, education, and project-coordination company. It does not offer financing, own systems, or give tax, legal, or investment advice. This article is educational and is not a guarantee of savings or outcomes.